U.S. patent application number 11/359526 was filed with the patent office on 2006-09-07 for drive unit.
This patent application is currently assigned to MITUTOYO CORPORATION. Invention is credited to Nobuyuki Hama.
Application Number | 20060196255 11/359526 |
Document ID | / |
Family ID | 36277181 |
Filed Date | 2006-09-07 |
United States Patent
Application |
20060196255 |
Kind Code |
A1 |
Hama; Nobuyuki |
September 7, 2006 |
Drive unit
Abstract
A drive unit is provided that is capable of providing a
high-accuracy measurement operation while suppressing a posture
change of a detector even if the detector is moved. The drive unit
includes a cross section of horizontally-oriented-U-shape guide
rail provided to a frame, and the outside to be parallel to the
movement direction of a roughness detector; a slider formed to be
able to freely slide along the guide rail, and configures a frame
being rectangular in cross section to include a detector therein;
biasing member that biases the slider against the guide rail; and
drive device that moves the slider along the guide rail. The drive
unit is configured to include a motor, a ball screw axis to be
driven by the motor, and a nut member that is screwed to the ball
screw axis, and is coupled to the slider. The ball screw axis is
disposed in the vicinity of the substantial center of sliding
surfaces of the slider.
Inventors: |
Hama; Nobuyuki; (Higashi
Hiroshima-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
MITUTOYO CORPORATION
KAWASAKI
JP
|
Family ID: |
36277181 |
Appl. No.: |
11/359526 |
Filed: |
February 23, 2006 |
Current U.S.
Class: |
73/105 |
Current CPC
Class: |
G01B 5/0009 20130101;
G01B 7/34 20130101 |
Class at
Publication: |
073/105 |
International
Class: |
G01B 5/28 20060101
G01B005/28 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 4, 2005 |
JP |
2005-061343 |
Claims
1. A drive unit that moves a detector along a surface of a
measurement work, comprising: a frame; a guide rail that is
provided to the frame; a slider that is provided to be able to
freely slide along the guide rail, and that holds the detector; a
drive device that moves the slider along the guide rail, wherein
the drive device includes a motor, a feed screw axis to be driven
by the motor, and the feed screw axis is disposed on an inner side
of the guide rail and inside of the slider.
2. The drive unit according to claim 1, wherein: the guide rail is
provided with two external guide surfaces that are parallel to a
movement direction of the detector, the two external guide surfaces
having a predetermined angle therebetween; and the slider is
provided with two internal sliding surfaces opposing the two
external guide surfaces, and is formed to have a shape that houses
therein the guide rail.
3. The drive unit according to claim 1, further comprising a
biasing device that biases the slider toward the guide surfaces of
the guide rail.
4. The drive unit according to claim 1, wherein the drive device
further includes a nut member that is screwed to the feed screw
axis and coupled to the slider.
5. The drive unit according to claim 1, wherein: the guide rail is
formed to have a horizontally-oriented substantially-U-shape in
cross section; the slider is formed to configure a rectangular
frame in cross section of housing therein the guide rail, and four
inner surfaces forming an end-surface rectangular frame are
provided to be able to freely slide with respect to the guide rail;
and the feed screw axis is disposed in a vicinity of a substantial
center of four sliding surfaces between the guide rail and the
slider in cross section.
6. The drive unit according to claim 2, further comprising a
biasing device that biases the slider toward the guide surfaces of
the guide rail, wherein the biasing device is provided on a side
surface of the slider opposite to one of the two internal sliding
surfaces of the slider and includes: a leaf spring whose one end is
fixed to the slider; a sliding member retained by the other end of
the leaf spring and abutting the guide rail; and a biasing force
adjustment mechanism that is provided on an opposite side of the
sliding member with the leaf spring therebetween, applies biases in
a direction in which the sliding member abuts the guide rail, and
is capable of adjusting a biasing force.
7. The drive unit according to claim 4, wherein: the slider and the
nut member are coupled together via a universal joint that allows a
small displacement of the nut member occurring in a direction
axis-orthogonal to the feed screw axis.
8. The drive unit according to claim 1, wherein the detector
includes: a detector main body; a stylus that is supported by the
detector main body to be able to freely swing, and is projecting a
sensing pin at a tip end at substantially 90 degrees; and a
detection section that detects a swing movement of the stylus,
wherein a detector rotation mechanism is included to rotate the
detector about an axis being substantially parallel to the movement
direction of the detector.
Description
BACKGROUND
[0001] JP-A-2001-133249 and JP-A-2002-71346 disclose a drive unit
and a surface texture measurement instrument. The drive unit moves
along the surface of a measurement work, and includes a detector
that measures the surface roughness, the surface rising and
falling, the contour, or other features of the measurement
work.
[0002] The drive unit of JP-A-2001-133249 is configured to include:
a guide rail having the cross section of downwardly-oriented
substantially-U-shape with two reference surfaces, which are
disposed parallel to the movement direction of the detector with an
angle of 90 degrees therebetween; a slider also having the cross
section of downwardly-oriented substantially-U-shape, being fit to
the outside of the guide rail to be able to freely swing, and keeps
hold of the detector in the guide rail; and drive device for moving
the slider along the guide rail. The drive device is configured to
include: a motor; a feed screw axis that is rotated by the motor;
and a feed piece screwed to the feed screw axis and coupled to the
slider. Therein, the feed screw axis is disposed at the position
above the slider to be parallel to the guide rail.
[0003] The surface texture measuring instrument of JP-A-2002-71346
is configured to include: a guide; a slider formed to configure a
rectangular frame in cross section to include the guide therein, is
fit to the outside of the guide to be able to freely slide, and is
keeping hold of a detector on the bottom surface; and drive device
for moving the slider along the guide rail. The drive device is
configured to include: a motor; a ball screw that is rotated by the
motor; and a nut screwed to the ball screw and coupled to the
slider. Therein, the ball screw is disposed at the position above
the slider to be parallel to the guide rail.
SUMMARY
[0004] In both the drive unit of JP-A-2001-133249 and the surface
texture measuring instrument of JP-A-2002-71346, the feed screw
axis and the ball screw for use of moving the slider are disposed
at the positions above the slider, which is supported by the guide
rail (or the guide) to be able to freely slide, i.e., the feed
screw axis and the ball screw are disposed at the positions at
which the center of gravity of the slider is off. Therefore, a
moment force is applied to the slider, thereby easily causing the
slider to change in posture with respect to the guide rail (or the
guide). Once the slider changes in posture, it will appear as a
measurement deviation at the time of measuring the surface
roughness, the surface rising and falling, the contour, or others.
As a result, there is a drawback of not leading to a measurement
operation with a high accuracy.
[0005] An object of the present disclosure is to provide a drive
unit that may provide assurances of a measurement operation with a
high accuracy while suppressing any possible posture change to be
occurred to a detector even if the detector is moved.
[0006] A drive unit is provided to move a detector along the
surface of a measurement work. The drive unit may include a frame;
a guide rail that is provided to the frame, and is provided with
two guide surfaces on the outside being parallel to the movement
direction of the detector with a predetermined angle therebetween;
a slider that is provided to be able to freely slide along the
guide rail, and is keeping hold of the detector; a biasing device
that biases the slider toward the guide surfaces of the guide rail;
and a drive device that moves the slider along the guide rail. The
slider may be provided with two sliding surfaces opposing to the
two guide surfaces, and is formed to have the shape of housing
therein the guide rail, and the drive device may include a motor, a
feed screw axis to be driven by the motor, and a nut member that is
screwed to the feed screw axis and coupled to the slider, and the
feed screw axis is disposed on the inner side of the guide rail and
inside of the slider.
[0007] The stylus may have the shape of housing therein the guide
rail, when the guide rail is cut in the direction orthogonal to the
longitudinal direction, including not only the shape enclosing
around the cross sectional contour of the guide rail but also the
shape covering most of the cross sectional contour thereof.
Moreover, the feed screw axis is not limited to the ball screw
axis, but may also be a screw axis formed by disposing a normal
screw along the outer rim surface.
[0008] With such a configuration, when the motor of the drive
device is driven, in response to the rotation of the feed screw
axis, the nut member is moved to the axial direction of the feed
screw axis. Accordingly, the slider is moved along the guide rail.
That is, the detector attached to the slider is moved along the
surface of a measurement work, and as a result, the surface texture
of the measurement work may be detected by the detector.
[0009] According to such a disclosure, the moment to be produced to
the slider may be suppressed to a further degree than conventional
due to the configuration that the feed screw axis is disposed on
the inner side of the guide rail and inside of the slider.
Therefore, even if the detector is moved, any possible posture
change to be occurred to the detector may be suppressed to possibly
minimum so that a measurement operation may be performed with
assurances of high accuracy.
[0010] What is more, the guide rail is formed with two guide
surfaces, which are so disposed as to form a predetermined angle
therebetween, being both parallel to the movement direction of the
detector. The slider is formed with two sliding surfaces, which are
opposing to the two guide surfaces. Therefore, any posture change
observed in the direction orthogonal to these two guide surfaces
and the sliding surfaces, e.g., four directions of up and down, and
right and left, may be suppressed to possibly minimum. Accordingly,
even if the measurement is performed by changing the posture of the
detector, the straightness accuracy may be guaranteed while the
posture change of the slider is suppressed so that the measurement
operation may be performed with accuracy.
[0011] With the drive unit of the present disclosure, preferably,
the guide rail is in the cross section of horizontally-oriented
substantially-U-shape. The slider is formed to configure a
rectangular frame in cross section to include therein the guide
rail, and four inner surfaces of the frame being rectangular at the
end surface are provided to the guide rail to be able to freely
slide. The feed screw axis is disposed in the vicinity of the
substantial center of the four sliding surfaces of the guide rail
and the slider.
[0012] According to such a disclosure, the four inner surfaces of
the end-surface rectangular frame of the guide rail may freely
slide, and the feed screw axis is disposed in the vicinity of the
substantial center of the four sliding surfaces of the guide rail
and the slider. Therefore the moment to be produced to the slider
is cancelled out, and as a result, any posture change to be
occurred to the detector may be suppressed with more certainty.
[0013] With the drive unit of the present disclosure, preferably,
the biasing member may include: a leaf spring whose one end is
fixed to the slider; a sliding member retained by the other end of
the leaf spring, and abuts the guide rail; and a biasing force
adjustment mechanism that is provided on the side opposite to the
sliding member with the leaf spring therebetween for bias
application in such a direction that the sliding member abuts the
guide rail, and is capable of adjusting the biasing force, and is
provided on the side surface opposite to each of the two sliding
surfaces of the slider.
[0014] According to such a disclosure, by the leaf spring fixed to
the slider causing the slider member to abut the guide rail, the
slider is biased in such a manner that the two sliding surfaces of
the slider follow the two guide surfaces of the guide rail so that
the slider is moved with reference to the two guide surfaces of the
guide rail. Therefore, accurately assuring the straightness of the
two guide surfaces accordingly provides assurances of the
straightness accuracy of the slider, i.e., the detector.
[0015] What is more, the configuration includes the biasing force
adjustment mechanism that is capable of adjusting the biasing force
that biases the sliding member in the direction abutting the guide
rail. Accordingly, through adjustment of the biasing force, the
pressure of the sliding member abutting the guide rail may be
arbitrarily set. Herein, the sliding member may be made of a
material of lower friction coefficient such as Teflon (trade mark).
With this being the case, even if the slider is biased toward the
guide rail by the biasing device including the leaf spring and the
sliding member, the friction force to be produced between the
surface of the sliding member abutting the guide rail and the guide
rail is not so high. Therefore, the slider may be made to slide
smoothly along the guide rail.
[0016] With the drive unit of the present disclosure, the slider
and the nut member are preferably coupled together via a universal
joint that allows a small displacement observed to the nut member
in the axial-orthogonal direction of the feed screw axis.
[0017] According to such a disclosure, the slider and the nut
member are coupled together via the universal joint that allows a
small displacement observed to the nut member in the
axial-orthogonal direction of the feed screw axis. With such a
configuration, any effects caused by the swing rotation of the feed
screw axis may be absorbed by the universal joint, and are not
transmitted to the slider. Also in this respect, the straightness
accuracy may be guaranteed for the slider.
[0018] With the drive unit of the present disclosure, the detector
is preferably provided with: a detector main body; a stylus that is
supported by the detector main body to be able to freely swing, and
from its tip end, a sensing pin is protruding at substantially 90
degrees; and a detection section that detects any swinging motion
of this stylus. It is also preferable to include a detector
rotation mechanism that rotates the detector about an axis being
substantially parallel to the movement direction of the
detector.
[0019] According to such a disclosure, the detector rotation
mechanism is provided for rotating the detector about an axis being
substantially parallel to the movement direction of the detector so
that the sensing pin may be changed in orientation depending on the
measurement portion of a measurement work. For example, the sensing
pin may be changed to orient downward, sideward, diagonally
downward, or others. This thus enables the roughness measurement at
any arbitrary position of the inner radius surface of a hole, the
roughness measurement of a vertical end surface, the dimension
measurement between vertical surfaces, or the like.
[0020] These and other features and details are described in, or
are apparent from, the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Various exemplary details of systems and methods are
described, with reference to the following figures, wherein:
[0022] FIG. 1 is a perspective view of an exemplary surface
roughness measuring Instrument;
[0023] FIG. 2 is a schematic view of an exemplary detector rotation
unit;
[0024] FIG. 3 is a perspective view of an exemplary X-axis drive
unit;
[0025] FIG. 4 is a vertical cross sectional view of the X-axis
drive unit of FIG. 3;
[0026] FIG. 5 is a diagram showing an exemplary biasing device for
use in the X-axis drive unit of FIG. 3;
[0027] FIG. 6 is a block diagram showing an exemplary control
unit;
[0028] FIG. 7 is a diagram showing an example of measuring the
inner surface of a hole;
[0029] FIG. 8 is a diagram showing an example of measuring a width
dimension between two flanges of a crankshaft;
[0030] FIG. 9 is a cross sectional view of an exemplary
modification of a guide rail and that of a slider;
[0031] FIG. 10 is a schematic diagram of an exemplary modification
of the detector rotation unit; and
[0032] FIG. 11 is a schematic diagram of another exemplary
modification of the detector rotation unit.
DETAILED DESCRIPTION OF EMBODIMENTS
[0033] FIG. 1 is a perspective view of an exemplary surface
roughness measuring instrument. This surface roughness measuring
instrument may include a base 1, a support 2 provided to stand on
the base 1, an X-axis drive unit 3 provided to the support 2 to be
able to move in the vertical direction, a detector rotation unit 4
serving as a detector rotation mechanism that is moved by the
X-axis drive unit 3 into a direction (X-axis direction) orthogonal
to the support 2, and a roughness detector 5 that is rotated by the
detector rotation unit 4 about an X-axis.
[0034] FIG. 2 is a schematic diagram showing the detector rotation
unit 4. The detector rotation unit 4 may include a cabinet 10 that
is moved by the X-axis drive unit 3 in the X-axis direction, a
motor 11 fixed inside of the cabinet 10, a rotation axis 14 that is
supported inside of the cabinet 10 to be rotatable on the same axis
as an output axis 11A of the motor 11 via a bearing 12, and keeping
hold of the roughness detector 5 at the tip end thereof, an axis
joint 15 that couples together the rotation axis 14 and the output
axis 11A of the motor 11, and an angle detection sensor 16 that
detects the rotation angle position of the rotation axis 14 (the
roughness detector 5).
[0035] The angle detection sensor 16 may include a rotation disk 17
including transparent holes at a regular pitch along the outer rim
fixed to the rotation axis 14, and a detection head 18 including a
light-emitting element and a light-receiving element, those of
which are so disposed as to oppose to each other with the rotation
disk 17 therebetween.
[0036] The roughness detector 5 may include a detector main body
5A, a stylus 5C that is supported by the detector main body 5A to
be able to freely swing, and from its tip end, a sensing pin 5B is
protruding at substantially 90 degrees, and a detection section 5D
that detects any swinging motion of this stylus 5C.
[0037] FIG. 3 is a perspective view of the X-axis drive unit 3. The
X-axis drive unit 3 may include a cabinet 20 provided along the
support 2 to be able to move in the vertical direction (refer to
FIG. 2), a frame 21 fixed inside of the cabinet 20, a guide rail 22
whose both ends are supported by the frame 21, a slider 24 provided
along the guide rail 22 to be able to freely swing, and is keeping
hold of the detector rotation unit 4, biasing device 31 for biasing
the slider 24 in such a direction that the sliding surface of the
slider 24 abuts the guide surface of the guide rail 22, and drive
device 41 for moving the slider 24 along the guide rail 22.
[0038] The guide rail 22 may have the horizontally-oriented U-shape
in cross section with two guide surfaces, which are so disposed as
to form a predetermined angle therebetween, being both parallel to
the movement direction of the roughness detector 5. For example, as
shown in FIG. 4, the guide rail is formed to have the
horizontally-oriented U-shape in cross section with an upper wall
22A, a side wall 22B that extends downward at 90 degrees from an
end of the upper wall 22A to be a piece therewith, and a lower wall
22D that extends in the horizontal direction from a lower end of
the side wall 22B to be parallel to and be a piece with the upper
wall 22A. On the outer side surface of the upper wall 22A, a first
guide surface 23A is formed, and on the outer side surface of the
side wall 22B, a second guide surface 23B is formed. The first
guide surface 23A and the second guide surface 23B are with
assurances of straightness accuracy.
[0039] The slider 24 may configure a rectangular frame in cross
section including the guide rail 22 therein. For example, as shown
in FIG. 4, the slider is formed to configure a vertically-longer
rectangular frame in cross section, including an upper wall 24A,
side walls 24A and 24C, and a lower wall 24D. The inner surface of
the upper wall 24A and the inner surface of the side wall 24B are
formed with two sliding surfaces opposing to the two guide surfaces
23A and 23B of the guide rail 22, i.e., a first sliding surface 25A
and a second sliding surface 25B, respectively.
[0040] Between the inner surfaces of the slider 24, i.e., those of
the upper wall 24A, the side walls 24B and 24C, and the lower wall
24D, and the outer surfaces of the guide rail 22, i.e. those of the
upper wall 22A, the side wall 22B, and the lower wall 22D, sliding
members 26A, 26B, 26C, and 26D are disposed, respectively. Herein,
between the inner surface of the upper wall 24A of the slider 24
and the outer surface of the upper wall 22A of the guide rail 22,
the sliding member 26A is provided at the center in the width
direction. Between the inner surface of the lower wall 24D of the
slider 24 and the outer surface of the lower wall 22D of the guide
rail 22, the sliding member 26D is provided at the center in the
width direction. Between the inner surface of the side wall 24B of
the slider 24 and the outer surface of the side wall 22B of the
guide rail 22, the sliding member 26B is provided above the other
sliding member 26B. Between the inner surface of the side wall 24C
of the slider 24 and the end surface of the upper wall 22A of the
guide rail 22, the sliding member 26C is provided, and between the
inner surface of the side wall 24C of the slider 24 and the end
surface of the lower wall 22D, the other sliding member 26C is
provided.
[0041] The biasing device 31 may be provided to the surfaces
opposing to the two sliding surfaces 26A and 26B of the slider 24,
i.e., the lower wall 24D and the side wall 24C. As shown in FIG. 5,
the biasing members 31 are each configured to include a leaf spring
32 whose one end is fixed to the slider 24, the sliding members 26C
and 26D provided to the other end of the leaf spring 32 via a swing
mechanism 33, and a biasing force adjustment mechanism 36 that is
provided on the side opposite to the sliding members 26C and 26D
with the leaf spring 32 therebetween to bias the leaf spring 32 in
such a direction that the sliding members 26C and 26D abut the
guide rail 22, and is capable of adjusting the biasing force.
[0042] The swing mechanism 33 may be disposed between the leaf
spring 32 and the sliding members 26C and 26D, and is configured to
include two plates 34A and 34B forming a conical groove at the
center of their inner surfaces facing to each other, and a steel
ball 35 that is accommodated in the conical groove of the two
plates 34A and 34B.
[0043] The biasing force adjustment mechanism 36 may include an
attachment member 37 fixed to the slider 24, an adjustment screw 38
screwed into the attachment member 37, and a spring 39 housed
inside of the adjustment screw 38.
[0044] The drive device 41 may include a motor 42 that is fixed to
the frame 21 to be parallel to the guide rail 22, a ball screw axis
47 fixed to the frame 21 to be parallel to the guide rail 22, and
serves as a feed screw axis that transmits the rotation of the
motor 42 via a rotation transmission mechanism 43, and a nut member
48 that is screwed into the ball screw axis 47, and coupled to the
slider 24 via a universal joint 51.
[0045] The rotation transmission mechanism 43 may include a pulley
44 attached to an output axis 42A of the motor 42, a pulley 45
fixed to one end of the ball screw axis 47, and a belt transmission
mechanism configured by a belt 46 that is wound around between the
pulleys 44 and 45. Note here that the rotation transmission
mechanism 43 is not limited to such a belt transmission mechanism,
and may be a gear transmission mechanism, a chain transmission
mechanism, or others.
[0046] The ball screw axis 47 may be disposed in the vicinity of
the substantial center of four sliding surfaces of the guide rail
22 and the slider 24 (the inner surface of the upper wall 24A of
the slider 24, the inner surface of the lower wall 24D thereof, and
the inner walls of the side walls 24B and 24C thereof). To be more
specific, the ball screw axis 47 is disposed at substantially the
center in the horizontally-oriented-U-shape inner space of the
guide rail 22.
[0047] The universal joint 51 may allow a small displacement of the
nut member 48 in the axis-orthogonal direction of the ball screw
axis 47, and includes a joint main body and two linear bushes.
[0048] The linear bush may be provided with a spindle axis, and a
sliding body that may freely slide smoothly along the spindle
axis.
[0049] First of all, to the nut member 48, a first spindle axis is
fixed in the horizontal direction being orthogonal to the ball
screw axis 47, and a first sliding body that slides the first
spindle axis is fixed to the joint main body. With such a
configuration, the joint main body is allowed to be able to freely
move only in the horizontal direction with respect to the nut
member 48.
[0050] To the joint main body, a second spindle axis is fixed in
the vertically downward direction being orthogonal to the ball
screw axis 47, and a second sliding body that slides the second
spindle axis is fixed to the slider 24. With such a configuration,
the joint main body is allowed to freely move only in the vertical
direction with respect to the slider 24.
[0051] With such a configuration, with respect to the slider 24,
the nut member 48 is provided with the movement flexibility only in
the vertical direction orthogonal to the ball screw axis 47 and the
horizontal direction. That is, the nut member 48 becomes able to
freely displace only in the axis-orthogonal direction of the ball
screw axis 47 without rotating about the ball screw axis 47. This
thus enables to move the slider 24 along the guide rail 22 while
the swing rotation of the nut member 48 resulted from the
straightness in the axis direction of the ball screw axis 47 is
allowed, thereby allowing the slider 24 to move straight with a
high accuracy.
[0052] Note here that the sliding member may be so configured as to
tilt with respect to the axis direction of a spindle axis except
for the axis-orthogonal surface (Y-Z plane) of the ball screw axis
47. Such a configuration may absorb any posture change occurred in
the X-Y plane or X-Z plane of the nut member 48 as a result of the
swing rotation of the nut member 48, thereby allowing the slider 24
to move straight with a higher accuracy.
[0053] FIG. 6 is a block diagram of a control unit. A control unit
61 may be connected with a Z-axis drive unit 6 that moves the
X-axis drive unit 3 in the vertical direction, the X-axis drive
unit 3, the detector rotation unit 4, the roughness detector 5, an
input unit 7, a display unit 8, and a storage unit 9.
[0054] The input unit 7 may input various command information,
including a measurement item selection command, a measurement start
command, or the like.
[0055] The display unit 8 may display the measurement items, the
measurement result, or the like.
[0056] The storage unit 9 may store an operation command program,
measurement result, or the like in accordance with the measurement
items.
[0057] At the time when the surface texture of a measurement work
is measured, first of all, the measurement work is placed on the
base 1 using a table or others. After the sensing pin 5B of the
roughness detector 5 is touched to the surface of the measurement
work, the roughness detector 5 is moved along the surface of the
measurement work.
[0058] For example, the motor 42 provided to the X-axis drive unit
3 is rotated. In response, the rotation force of the motor 42 is
transmitted to the ball screw axis 47 via the rotation transmission
mechanism 43. Once the ball screw axis 47 is rotated, the nut
member 48 screwed into the ball screw axis 47 moves forward or
backward so that the slider 24 and the roughness detector 5 fixed
to the nut member 48 move forward or backward (move) along the
guide rail 22. Once the roughness detector 5 is moved along the
surface of the measurement work, from any displacement observed to
the sensing pin 5B (the stylus 5C) in the vertical direction, the
surface roughness or others of the measurement work is
detected.
[0059] Here, for changing of the orientation of the sensing pin 5B
of the stylus 5C, a command is issued from the input unit 7 about
the orientation of the sensing pin 5B. In response, the motor 11
provided to the detector rotation unit 4 is rotated. Once the motor
is rotated, the rotation axis 14 is also rotated, and as a result,
the roughness detector 5 is rotated. The rotation angle of the
roughness detector 5 is detected by the angle detection sensor 16,
and the resulting angle information is provided to the control unit
61. When the angle information provided by the angle detection
sensor 16 is the same as the angle that is previously input, the
control unit 61 stops driving of the motor 11. In this manner, the
sensing pin 5B of the stylus 5C is set to any designated
orientation.
[0060] By changing the orientation of the sensing pin 5B of the
stylus 5C depending on the measurement portion of a measurement
work, the following measurement may be implemented together with
the downward measurement.
[0061] FIG. 7 shows an example of measuring the surface roughness
of the inner surface of a hole 101 of a measurement work 100. With
the posture that the sensing pin 5B is oriented downward, the
bottom side surface of the inner surface of the hole 101 may be
subjected to the measurement operation. With the posture that the
sensing pin 5B is oriented sideward, the side surface of the inner
surface of the hole 101 may be subjected to the measurement
operation, and with the posture that the sensing pin 5B is oriented
upward, the top side surface of the inner surface of the hole 101
may be subjected to the measurement operation.
[0062] FIG. 8 shows an example of measuring a width dimension W
between two flanges 103 and 104 formed to a crankshaft 102. First
of all, with the posture that the sensing pin 5B is oriented
sideward, the outer surface of the flange 103 is measured.
Thereafter, the sensing pin 5B is so rotated as to be in the
opposite sideward posture, and the outer surface of the other
flange 104 is measured. In this manner, the width dimension W
between the two flanges 103 and 104 may be measured.
[0063] According to such an embodiment as above, the following
effects may be achieved.
[0064] (1) With the detector rotation unit 4 that rotates the
roughness detector 5 about an axis of the stylus 5C, the sensing
pin 5B may be changed in orientation depending on the measurement
portion of a measurement work. For example, the sensing pin 5B may
be changed in orientation to direct downward, sideward, upward,
diagonally upward or downward, or others. This thus possibly
increases the measurement area so that any arbitrary position on
the inner radius surface of a hole becomes available for roughness
measurement.
[0065] (2) Because the ball screw axis 47 is disposed on the inner
side of the guide rail 22 and inside of the slider 24 for driving
the slider 24 that keeps hold of the roughness detector 5, the
moment to be produced to the slider 24 may be suppressed to a
further degree compared with conventional. Therefore, when the
roughness detector 5 is moved, the posture change of the roughness
detector 5 may be suppressed to possibly minimum so that the
measurement may be performed with high accuracy for sure.
[0066] For example, the guide rail 22 is in the cross section of
horizontally-oriented substantially-U-shape, the slider 24 is
formed to configure a rectangular frame in cross section, and the
ball screw axis 47 is disposed in the vicinity of the substantial
center of four sliding surfaces of the guide rail 22 and the slider
24, i.e., disposed with friction force oriented. With such a
configuration, the moment produced to the slider 24 is cancelled
out, and the posture change of the roughness detector S may be
suppressed with certainty.
[0067] (3) The guide rail 22 is formed with the two guide surfaces
23A and 23B, which are so disposed as to form a predetermined angle
therebetween, being both parallel to the movement direction of the
roughness detector S. The slider 24 is formed with the two sliding
surfaces 25A and 25B, which are opposing to the two guide surfaces
23A and 23B. Therefore, any posture change observed in the
direction orthogonal to these two guide surfaces 23A and 23B, and
the sliding surfaces 25A and 25B, e.g., four directions of up and
down, and right and left, may be suppressed to possibly minimum.
Accordingly, even if the measurement is performed by changing the
posture of the roughness detector 5, the straightness accuracy may
be guaranteed while the posture change of the slider 24 is
suppressed so that the measurement operation may be performed with
accuracy.
[0068] (4) The biasing device 31 is each provided to surfaces
opposite to the two sliding surfaces 25A and 25B of the slider 24.
With such a configuration, the slider 24 is biased in such a manner
that the two sliding surfaces 25A and 25B of the slider 24 follow
the two guide surfaces 23A and 23B of the guide rail 22 so that the
slider 24 is moved with reference to the guide surfaces 23A and 23B
of the guide rail 22. Therefore, accurately assuring the
straightness of the two guide surfaces 23A and 23B accordingly
guarantees the straightness accuracy of the slider 24, i.e., the
roughness detector 5.
[0069] (5) The biasing device 31 is configured to include the leaf
spring 32 whose one end is fixed to the slider 24, the sliding
members 26C and 26D retained by the other end of the leaf spring
32, and the biasing force adjustment mechanism 36 that is provided
to the side opposite to the sliding members 26C and 26D with the
leaf spring 32 therebetween, and is capable of adjusting the
biasing force to be applied to the guide rail 22. With such a
configuration, through adjustment of the biasing force of the
biasing force adjustment mechanism 36, the pressure of the sliding
members 26C and 26D abutting the guide rail 22 may be arbitrarily
set. As such, through appropriate adjustment of the pressure of the
sliding members 26C and 26D abutting the guide rail 22, the slider
24 may be made to slide smoothly along the guide rail 22.
[0070] (6) The slider 24 and the nut member 48 are coupled together
via the universal joint 51 that allows a small displacement of the
nut member 48 in the direction axis-orthogonal to the ball screw
axis 47. With such a configuration, any effects caused by the swing
rotation of the ball screw axis 47 may be absorbed by the universal
joint 51, and are not transmitted to the slider 24. Also in this
respect, the straightness accuracy may be guaranteed for the slider
24.
[0071] Note here that the present disclosure is not restrictive to
the above-described embodiment, and numerous other modifications
and variations devised for achieving the object of the present
disclosure may be included in the present disclosure.
[0072] For example, in the above-described embodiment, the guide
rail 22 is formed to have a cross section of horizontally-oriented
substantially-U-shape, and the slider 24 is formed to configure a
frame being rectangular in cross section to include the guide rail
22 therein. This is surely not restrictive, and the following shape
will do.
[0073] FIG. 9 shows the guide rail 22 formed to have an L-shape in
cross section, and the slider 24 formed to have a
downwardly-oriented U-shape in cross section.
[0074] Such shapes may also lead to the effects similar to the
above-described embodiment.
[0075] The configuration of the detector rotation unit 4 is not
restrictive to the configuration described by referring to FIG. 2,
and the following configuration will also do.
[0076] FIGS. 10 and 11 illustrate modification of a detection
rotation unit. Compared with the detector rotation unit 4 of FIG.
2, the detector rotation unit 4 of FIG. 10 is different therefrom
only in the respect that the rotation of the motor 11 is
transmitted to the rotation axis 14 via two transmission gears 13A
and 13B.
[0077] Compared with the detector rotation unit 4 of FIG. 10, the
detector rotation unit 4 of FIG. 11 is different therefrom only in
the respect that a manual knob 19 is provided as an alternative to
the motor 11.
[0078] In the X-axis drive unit 3 of the above-described
embodiment, the ball screw axis 47 is provided in line with the
axis of the motor 42. This is surely not restrictive, and the ball
screw axis 47 and the axis of the motor 42 may be disposed in
series. Moreover, the drive device 41 may be provided with a
decelerator or others so as to adjust the movement speed of the
roughness detector 5.
[0079] The present disclosure is applicable to, in a surface
roughness measuring instrument for measuring the surface roughness
of a measurement work, and a contour measuring instrument for
measuring the surface rising and falling, the contour, or others of
a measurement work, a drive unit that moves such detectors along
the surface of the measurement work.
[0080] While various details have been described, these details
should be viewed as illustrative, and not limiting. Various
modifications, substitutes, improvements or the like may be
implemented within the spirit and scope of the foregoing
disclosure.
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